Display apparatuses include Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD) using an electro-optic effect, a Plasma Display Panel (PDP) using a gas-discharge and an Electro Luminescence Display (ELD) using electro-luminescence effect. Among the display apparatuses, the study on the LCD has been actively performed.
The LCD is a light receiving device that displays an image by controlling the amount of light from the outside, so that the LCD requires additional external light source, such as a backlight unit.
The backlight unit employs a Light Emitting Diode (LED) or a light emitting lamp, such as a Cold Cathode Florescent Lamp (CCFL).